kellerman: effect of boron on vegetation 483 



of vegetation. Furthermore, those familiar with the topography 

 of these deserts will recall the peculiar absence of vegetation from 

 mud fiats even when these are gradually drying out; they occa- 

 sionally dry into perfectly level plains, hard and smooth, appar- 

 ently not badly troubled with alkali but with no sign of vegeta- 

 tion. These play a formations in the vicinity of Hazen and Fallon 

 in the Truckee- Carson region, have been given more or less 

 consideration with studies of the alkali difficulties of the Truckee- 

 C arson irrigation project. While some of the reasons for the 

 refractory character of these soils have been traced to the im- 

 permeability of soils, ^ other areas that appeared too low in total 

 salt concentration to be dangerous to crop production were not 

 complicated by unusual colloid problems and yet remained 

 practically barren. 



In view of the records of the lather wide distribution of borax 

 in this region, it seems not unreasonable to suggest that the 

 irregular and rather definitely located occurrence of borax may 

 explain the injury to plants on these small areas. The number of 

 localities in which commercial borax production has been at- 

 tempted in the West will be surprising to most people. The 

 areas in which commercial borax development has taken place 

 within recent years or is now under way are well set out in the 

 section on borax from the 19 13 report on "Mineral Resources 

 of the United States."^ 



It should be remembered, however, that the deposits of borax 

 ordinarily are not recorded either by the geologists or com- 

 mercial prospectors unless of considerable magnitude. It is not 

 improbable, therefore, that the areas now recorded as showing 

 borax report only a small fraction of the deposits which, from 

 an agricultural or botanical point of view, are of prime significance. 

 From the data reported by Mr. Yale and Mr. Gale, and from 

 reports of other investigators, the following list apparently repre- 

 sents the areas in the United States where compounds of boron 

 have been found. 



^ KjellERMAN, Karl F. The relation of colloidal silica to certain impermeable 

 soils. Science 33: 189. 191 1. 



^ Yale, Charles G., and Gale, Hoyt S. The production of borax in IQ13. Min- 

 eral Resources of the U. S., 1913 — Part II. 1914. 



